Service manual

Measurement
Uncertainty
Calculations
Measurement uncertainties for the Datron 4708 source are calculated using
the 90-day accuracy specifications in the Datron 4708 User’s Handbook:
Measurement Uncertainty = Datron Accuracy + Calibration Uncertainty,
where Datron Accuracy (ppm) = Accuracy Relative to Calibration
Standards =
±(ppm OUTPUT + ppm FS)
and FS = 2 x range for all ranges except 1000V
FS = 1100 for the 1000V range
The assumed test conditions are:
• Temperature of 23
o
C±1
o
C
• 90 days since calibration
• 4-wire sense function for ohms measurements
Calculate DCV
Measurement
Uncertainty
From Section 6 - Specifications of the Datron 4708 User’s Handbook, DC
Voltage (Option 10) Accuracy (90 days since calibration and 23
o
C ±1
o
C)
follows, where Datron Accuracy =
±(ppm OUTPUT + ppm FS).
Datron
OUTPUT
(DCV)
Datron
Range
(Volts)
Datron
Accuracy
(ppm)
Calibration
Uncertainty
(ppm)
0.1
0.9
7.0
58.0
300.0
1.0000000V
1.0000000V
10.000000V
100.00000V
1000.0000V
2 + 0.4
2 + 0.4
1 + 0.15
2 + 0.25
3 + 0.25
2
2
1.5
2
2
Example: Calculate DC Voltage Measurement Uncertainty
Since Measurement Uncertainty = Datron Accuracy + Calibration
Uncertainty, for a 7.0 DCV OUTPUT and the Datron 4708 range set to
10.000000 V, Measurement Uncertainty (
µV)=±[(1.0 x 7.0) + (2 x 0.15 x
10)] + (1.5 x 7.0)] = ±20.5 µV = ±0.000021 V.
Or, with a 300 DCV OUTPUT and the 1000.0000V range, Measurement
Uncertainty (
µV) = ±[(3.0 x 300) + (0.25 x 1100)
+ (2.0 x 300)] =
± 1775 µV = ±0.001775 V.
66 Calculating Multimeter Accuracy Agilent E1411A/E1411B Service Manual